3G2 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 3, 



or dip at a high angle to the N.E., that is, towards the porphyry 

 and opposite to the general dip ; and as they come nearer to the 

 igneous rock, both dip and direction are frequently and considerably 

 changed, their colour becoming more intensely red, and they include 

 numerous subordinate arenaceous beds of various dimensions, of a 

 much harder texture, and chiefly composed of quartz*. An actual 

 junction of the slate with the porphyry I could not find, but close 

 by the latter there is a conglomerate rock in which the fragments 

 are rounded. These last consist of the same materials as the hard 

 quartzose beds in the slate above-mentioned, but they appear to be 

 mixed up in some degree vpith the porphyritic matter, and the rock 

 has some resemblance to the trappean conglomerate found near 

 Exeter, and at Dunchideock, north of Chudleighf. 



On its western side, the porphyry rises up from the shore like a 

 wall, facing the S.W. ; on its eastern side it also rises up with a 

 mural face, and here looking to the N.E. Immediately adjoining 

 this eastern side we find a conglomerate similar to that on the western 

 side J. On the west it is of greater thickness than on the east, and 

 contains more fragments of slate. On the eastern side the conglo- 

 merate has an indistinctly-marked bedded structure. It is succeeded, 

 that is eastward, by red slaty arenaceous beds, very much mottled 

 and striped with green, similar in appearance to the light patches in 

 the red porphyry. Frequently there are alternate stripes of red and 

 green slate in the direction of the laminae, but these green stains 

 occur in all forms, sometimes shading off, at others bounded by a 

 sharp well-defined line§. 



These last slate rocks are succeeded eastward by others having a 

 more decidedly argillaceous and shining structure ; still ranging 

 W.N.W., and dipping at various angles S.W. by W., that is, having 

 the same direction and dip as the slates westward of the porphyry, 

 and very much traversed by quartz veins. 



I traced the porphyry into the interior of the country ; first in 

 some quarries not far distant from the shore in the road from King- 

 sand to Millbrookjl. It has there the same apparently bedded 

 structure, the beds being from 15 to 30 inches thick, and bearing 

 W.N.W. I again found it in situ two miles distant, near the farm 

 of Trevvinnow, presenting the same aspect and with green spots as on 

 the shore, and in the same line of bearing, with slate at no great 

 distance on each side of it, so that there is every probability of its 

 being a prolongation of the great mass on the shore. 



Interstratified with the ordinary slate, and traversed, in common 

 vdth it, by quartz veins, I found on the shore, under high-water 

 mark, on the east of the porphyry and very near to it, a schistose 



* Specimens No. 3, the red slate ; 4 and 5, the hard arenaceous portions ; from 

 the western side of the porphyry and near the eastern end of Kingsaud. 



t Specimens No. 6, 7, 8 ; from the western side of the porphyry. 



X Specimens Nos. 9 & 10, from the eastern side of the porphyiy. 



§ Specimen No. 11, variegated slate from the eastern side; No. 12, a hard 

 quartzose bed, interstratified with 11, and similar to Nos. 4 & 5 from the western 

 side. II Specimens Nos. 13 & 14. 



